Zero turning radius (“ZTR”) mowers have at least one independently powered drive wheel on each side of a frame. Hydrostatic transmissions transmit power to each of the left and right drive wheels, either in forward or reverse. The pair of hydrostatic transmissions, or dual hydrostatic transmission, may be driven by an internal combustion engine. The independent rear drive wheels allow the ZTR mower to turn on a vertical turning axis. The vertical turning axis may be centrally located between the pair of hydrostatic transmissions.
ZTR mowers may have frames with left and right longitudinal frame members supported on a forward end by front wheels and extending rearwardly to support an internal combustion engine behind the operator seat and rear wheels. A mower deck may be suspended between the front and rear wheels. A seated operator may use left and right control levers or other steering controls to control the pair of hydrostatic transmissions driving the left and right rear drive wheels.
ZTR mowers also may have roll over protection systems, or ROPS, mounted to the vehicle frame behind the operator seat for preventing the vehicle from crushing the operator if the mower accidentally rolls over. U.S. Pat. No. 7,971,904 for Roll over protection system shows steel tubing bent into a desired shape with each of the lower legs including an arced or curved portion between an upper portion and a horizontal or nearly horizontal portion mounted to the vehicle frame. The upper portion of the ROPS may be vertical or inclined forwardly, and may be hinged to each of the lower legs with a pivot bracket so that the upper portion may be folded down and lowered.
Some ZTR mowers have water cooled engines with radiators mounted at various locations behind the operator seat. For example, U.S. Pat. No. 7,866,426 for Radiator support structure shows a radiator mounted behind the operator seat, under and between the pair of lower legs or support columns of the ROPS. Mounting the radiator under the ROPS allows the space to be utilized efficiently. However, if the ZTR mower rolls over or on its side, there is a risk that the ROPS may penetrate, crush or puncture the radiator, which might result in hot fluids leaking from the radiator near the operator. A ZTR mower radiator mounting structure is needed that reduces the risk that a ROPS might penetrate, crush or puncture the radiator if the mower is in a roll over position.